Clinical Study to Compare the Efficacy and Safety of Macitentan and Tadalafil Monotherapies With the Corresponding Fixed-dose Combination Therapy in Subjects With Pulmonary Arterial Hypertension
The purpose of this study is determine if a fixed-dose combination of the drugs macitentan and tadalafil is more effective than therapy with macitentan or tadalafil alone to treat pulmonary arterial hypertension.